Re: [C PATCH] fix aliasing for structures/unions with incomplete types

[Joseph Myers <josmyers@redhat.com>]

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On Tue, 2 Apr 2024, Martin Uecker wrote:

> Am Dienstag, dem 02.04.2024 um 20:42 +0000 schrieb Joseph Myers:
> > On Tue, 2 Apr 2024, Martin Uecker wrote:
> > 
> > > [C23]fix aliasing for structures/unions with incomplete types
> > > 
> > > When incomplete structure/union types are completed later, compatibility
> > > of struct types that contain pointers to such types changes.  When forming
> > > equivalence classes for TYPE_CANONICAL, we therefor need to be conservative
> > > and treat all structs with the same tag which are pointer targets as
> > > equivalent.
> > 
> > I don't see how what it done is actually about "which are pointer 
> > targets".
> 
> Right, I see now that the description needs to be improved. This refers
> only to targets of pointers included somewhere in the type we process
> for purposes of determining the equivalence class of this type (but
> not for other contexts).

A detailed self-contained description of the TYPE_CANONICAL / aliasing 
logic also needs to go somewhere in a comment in the source code rather 
than only in commit messages / emails.

-- 
Joseph S. Myers
josmyers@redhat.com